It is a continuous effort of the computer industry to improve the storage capacity and the operating characteristics of storage facilities of digital computers. Various steps have been taken to increase storage capacity of rotating disk storages. Recording data at higher recording densities within the storage tracks, and reducing the track width and track spacing are two of the most often used approaches for improving storage capacities. However, changing the recording and track densities require modification of the transducer-disk interface. Furthermore, changing the track density requires additional modification of the actuator mechanism, which moves the transducer across the disk storage surface to the desired tracks. None of these methods allow to upgrade a disk storage in the field. In general the user has to exchange the storage facility in order to upgrade his system.